Yieldable device



March 20, 1945. s. SCHNELL 2,372,023

YIELDABLE DEVICE Filed Aug. 26, 1942 2 Sheets-Sheet l ATTORNEY I I Patented Mar. 20, 1945 I :nEyIcn.

Steve Schnell, Kirkwood, Mo., assignor to Wagner,

Electric Corporation; St. Louis Mo, a corpora:

tion of Delaware Application Augustzs, isiz s'ei-ial No: 456,156;

. 5. Claims. (or. 267L641? My invention relates to improvements in yieldable devices and more particularly to that type of device in which relatively movable-members maintain body of non-compressible fluid and a bod-yof compressible fluid under pressure with said fluids being separated by a movable wall.

, One of. the objects of my invention is toprovide, in a yieldable device of the type referred to, improvedmeans for separating the fluids;

Another object of my invention is to seconstruct a yieldable deviceof. the; type-referred to that it will be simple in construction, eflicient in operation, and also easy tocondition for proper operation.

Other objects of my invention will become apparent from the following description taken i i-connection with the accompanying-drawings in which Figure lis a view of: my improved yieldable device showing itbeing. employed as 'a strut between a wheel andbody of a vehicle;

Figures 2 and 3 are longitudinal sectional views of the upper and lower parts of the yieldable device showing the inner construction thereof Figure 4 is a sectional View taken on the. line 4.--4 of Figure 3; and- Figure 5; is an enlarged sectional View ofthe filler plug construction.

Referring to the drawings in detail and first to Figure 1, I have shown my improved yieldable device I employed, by way. of. example, as a strut between a wheel of a vehicle. and. the, chassis or body thereof. that the device may be used wherever it, is do:- slredito have a yieldable support; a suspension device, a rebound control device, a shock absorbing device, an energy storing device, and so forth. As shown in Figure 1, arm 2 is pivoted However, it, is noted at one end to a part of theflchassis orbody 3 of a vehicle and its other end has rotatably mounted thereon a wheel 4. and another body part 5 of the vehicle there is interposed the" device or strut l, the connection being made by ball and socketconnections 5 and.'|..

- The. yieldable device or struts! is shown in.

detail in Figures 2, 3, 4 nd 5, reference towhich is" now made. The strut is; composed of two telescoping cylinders 8-and 9, the former being closed at its upper end by a ca 10 provided with a ball I l forming part of the ball and socket connection! and the latter being closed-at-dts lower-end by a cap 12 providedwith a. socket l3; for receiving ball l4 ofthe ball and socket connection 6,. said ball being held in thesocket bya p1ate'l5. The external diameter-otcylinder-B somewhat lessl than. theginternal, diamer Between arm 2 tEItOf cylinder 9;thus producing a chamber It between the walls. of; the. two cylinders. The lower-end of cylinder 8', which is received in cylinder 9;, carries a sleeve l1; whichzhasasuch an external diameter. asrto. snugly fitinvcylinder: 9

so asqto'properlyguide the. lower end of cylinder 8:. This sleeve is-providedwith; a plurality of circumferentially. spaced openings; l8 for placing chamber; I 6 in" communication with the interioeoi; cylinder 9 bBlOWgthQSlBGVt-B;

The.-upper-endoi; cylinder 9'carriesbearing sleevesv l9.-- and 20:between ;which is interposed suitable: annular packing meansZI-yto prevent fluidffrom leaking past the two cylinders yet permitting the: cylinders tohave relative axial movement; The, bearingzsleeves and-packing means are held in position. by aretaining cap 1-2) securedto the upper end of cylinder 9.

Within. the upper partof cylinder 8 there -is positioned an annular corrugated diaphragm or bellows like member 23 madeof rubber; synthetic rubber, or any other suitable material; The upper endof the: diaphragm is clamped to. the

' extreme upper end ofthe-cylinderand.the cap Ill-by a. member held in. clampingposition by 'a bolt 25.. This endof. the diaphragm'communicates with. an inlet passageze ln the cap, which passage is controlled, by an ordinary air pressure valve 21.. The lower end of diaphragm 23sis secured to' apiston. likepgu-ide. member 28 havingna loose fit in the cylinder andforming no obstruction. to, interchange of. fluid from op o-.

sitelsides thereof.- The connection ,between the lower end of the diaphragm and member 28 comprises-a threaded member 29 for closing. the open end thereof, and nut 30. The. diaphragm 13, is of suchmoldedlengthl that it can be stretchedfandcompressed a considerable longitudinal distance. Thusit is seen that by means ofthecorrugated. diaphragm there is provided inthe cylinders two chambers. A and Boom,- prising the interior; of the diaphragm, and the latter comprising all the. space inlthe two, cylinders. which is. notwithin the diaphragm., Cham IberiB is'to be filled with asuitable n0n-compressible fluid, such as 011,, hydraulic brake fluid, or the like, and chamber Aisto be filled with a compressible fluid-under pressure, preferably air. With chamber A containing a-compressible fluid; the pressures existing in both chambers will be the same since therdiaphragmnacts solely as a partition between the two bodies of fluid.

- The-chamber B is adapted to be yfiHBd..-Wlth fiuid-tl'rrouglr-an inlet passage .31. {ne war -the;=;.1ower2 end of @cylinder 9.1-. Thispassage is controlled by a filler plug construction generally indicated by the numeral 32 which, as shown in Figure 5, comprises a member 33 threaded into a threaded opening 34 and having a passage 35. This passage 35 is controlled by a check valve in the form of a valve element 36 and a spring 31, said check valve preventing fluid from flowing out of chamber B through passages 3| and 35 but not preventing fluid from being forced into chamber B when under a slight pressure. As a safety feature to prevent any fluid from coming out of chamber B, due to leakage of valve element 36, there is provided a plug. 38 screwed into the outer end of passage 35.

In order that the cushioning or shock absorbing action of the compressible fluid may be prop-' erly controlledwhen cylinder 8 moves inwardly with respect to cylinder 9, metering means is provided between the lower ends of the cylinder.- This means comprises a wall 39 clamped to the lower end of cylinder 8 by sleeve 11, said wall being provided with a central opening 49. Co-

I operating with this opening is a tapered pin 4! carried by cap I2 and extending into the lower part of cylinder 9 along its axis. The taper of the pin is such that the area of the opening 49 will be decreased as cylinder 8 moves inwardly with respect to cylinder 9. Thus it is seen that by this arrangement as the cylinder 8 moves inwardly, the rate of flow of-fluid between the lower part of cylinder 9 and the lower part of cylinder 8 will be decreased, thereby progressively decreasing the rate of movement of cylinder 8 inwardly. It is also noted that by this action increasing of the pressure of the fluid in chamber A will be gradual, thereby causing the proper shock absorbing action. I

When cylinder 8 moves inwardly with respect to cylinder 9 the volume of chamber I6 between the two cylinders increases and fluid flows through the plurality of passages l8. However, when cylinder 8 moves outwardly with respect to cylinder 9, the metering action through opening 49 is not effective and in order to control the outward movement of cylinder 8, a control ring 42 is provided which is adapted to cooperate with the top of-sleeve l'l.- This ring has two diametrically positioned openings 43 and in order that these openings may communicate with all the passages I8 when the ring is seated, there is provided an annular groove 44 at the top of sleeve I! which connects withall the passages. Thus when cylinder 8 moves outwardly with respect to cylinder 9, ring to will seat on the top of sleeve I1 and all fluid which flows from chamber IE to the lower end of cylinder 9 must pass only through the'two openings 43. The ring, however, does not interfere with the movement of the fluid from the lower end of cylinder 9 to chamber I8 when cylinder 8 moves relativelyinwardly with respect to cylinder 9 since under these conditions the fluid flowing through the passages l8 will unseat the, ring. The upward movement of the ring is limited by a shoulder 45. In filling the yieldable device the'cylinders 8 and 9 are first separated as far as possible. Next, just a sufficient amount of air under pressure is placed within chamber A to elongate the diaphragm and cause the piston like member 28 to engage with wall 39 at the lower end oi cylinder 8. The filler plug 38 is now moved and the non-compressible fluid under slight pressure forced into chamber B. When this chamber is completely filled, there will be fluid in surrounding relation to the diaphragm 23 and also within chamber It. In order that all the air may be expelled from chamber B during the filling operation, there is provided a bleeder plug 45 at the top end of cylinder 8, this being opened during the filling operation. If there should be some air trapped in chamber I6 during the filling operation, this can be freed by moving cylinders 8 and 9 relatively to each other. After chamber B is filled and all air expelled, the bleeder plug 46 is closed and safety plug 38 screwed into sealing position. Additional air under pressure is next placed in chamber A so that proper operation can take place. When the device is used asa strut on a vehicle, this amount of air will be sufficient to have the cylinder 3 telescoped in cylinder 9 about half way.

With the yieldable device filled with the two fluids as described, said fluids will be confined to their respective chambers and there will be no possibility of them becoming mixed. The diaphragm will not collapse in any way due' to the fact that the pressures in chambers A and B i will always be equal.

With the strut in operative condition when wheel 4 moves over uneven surfaces, cylinders 8 and 9 will have relative movement with each other due to the fact that the force acting on the yieldable device will vary. As the force increases, cylinder 8 will be moved inwardly with respect to cylinder 9. This will cause fluid to flow into chamber I6 from the lower end of cylinder 9 and also from this lower end of cylinder 9 into the lower end of cylinder 8 since when cylinder 8 moves into cylinder 9'it will displace fluid and the only place it can go is into chamber I6 and the lower end of cylinder 8 which has a yieldable wall. The fluid flowing into cylinder 8 results'in a decrease in the volume of chamber A and consequently diaphragm 23 will be shortened. The shortening of the. diaphragm will increase the pressure of the air in chamber A and thereby cause an added resistance to the downward movement of cylinder 8 with respectto cylinder 9. Thus the compressing of the air cushions the vehicle. This cushioning is controlled'by decrease'of the rate of flow of fluid through opening' m, particularly when the forces tending to move the cylinders inwardly toward each other are as great as when the vehicle passes over a large obstruction or an embankment. When wheel 4 and the body of the vehicle move relatively away from each other, cylinder 3 will be moved outwardly with respect to cylinder 9 but the rate of outward movement will be controlled by the two openings 43 in ring 42. Thus there is no possibility of the cylinders being completely separated to their fullest extent by any rapid movement.

From the foregoing it is seen that by the us of the annular corrugated diaphragm the two fluids in chambers A and B will be positively maintained separated and without any possibility of there being unequal pressures in the two chambers A and B as the collapsing and distending of the diaphragm is completely without friction. The length of the diaphragm permits the cylinders to have their full relative movement and because of the number of corrugations, there will be no strain on the material. This arrangement also facilitates easy and proper filling of the two chambers so thattheyieldabledevice can be conditioned for proper operation. The diaphragm 23 is so constructed that when it is completely elongated with the piston like member 28 in engagement with wall 39 and the cylinders separated to their fullest extent, chamber B will have a volume equal to the correct volume of non-compressible fluid for the device. Thus there will be no possibility of getting too much or too little non-compressible fluid in chamber B. The necessity of measuring the fluid before filling chamber Bis eliminated.

Being aware of the possibility of modifications in the particular structure herein described without departing from the fundamental principles of my invention, I do not intend that its scope be limited except as set forth by the appened claims.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent of the United States is: a

1. In a yieldable device for interpositioning between two members having relative movement, two telescoping cylinders closed at their outer ends, a single annular corrugated diaphragm secured at one end to the outer end of one of the cylinders and closed at the other end, said diaphragm providing by axial elongation and contraction a variable sealed chamberbetween its walls and within said one cylinder, a substantially non-compressible fluid filling the space in the cylinders which is exterior to the diaphragm,

a compressible fluid under pressure in the chamber formed by the diaphragm, and means comprising an element carried by each cylinder for progressively restricting the flow of the non-compressible fluid between the cylinders as they move relatively inwardly.

2. In a yieldable device for interpositioning between two members having relative movement, two telescoping cylinders closed at their outer ends, a single annular corrugated diaphragm secured at one end to the outer end of one of the cylinders and closed at the other end, said diaphragm providing by axial elongation and contraction a variable sealed chamber within said one cylinder, a substantially non-compressible fluid filling the space in the cylinders whichis exteriorto the diaphragm, a compressible fluid under pressure in the chamber formed by the diaphragm, means comprising an element carried by each cylinder for progressively restricting the flow of the non-compressible fluid between'the cylinders as they. move relatively inwardly, and means for checking the rate of separation as the cylinders move relatively outwardly.

3. In a yieldable device for interpositioning between two members having relative movement, two telescoping cylinders having their outer ends closed, means comprising a corrugated, member secured at one end to the outer end of the inner cylinder and closed at its other end, said member providing by axial elongation and contraction a variable chamber, a substantially non- I compressible fluid filling the space in the cylinders which is exterior to the corrugated member including its side wall, a compressible fluid under .pressure in the chamber formed by said corrugated member, a wall carried by the inner end of the inner cylinder and provided with an opening, and a tapered pin carried by the'outer cylinder and extending through the wall opening to pro vide a progressively decreasing passage between the cylinders as they move relatively toward each other from any point where the pin is received in' the opening.

4. In a yieldable device for interpositioning between two members having relative movement, two telescoping cylinders having their outer ends closed, means comprising an annular corrugated member secured: at one end to the outer end of the inner cylinder and closed at its other end to provide an axial elongation and contraction a variable chamber, a substantially non-compressible fluid filling the space in the cylinders which is exterior to the corrugated member, a com-' pressible. fluid under pressure in the chamber formed by asid corrugated member, a wall carried by the inner end of the inner cylinder and 1 i provided with an opening, a tapered pin carried by the outer cylinder and extending through the wall opening to provide a progressively decreasin passage between the cylinders as they move relatively toward each other, and means carried by the closed end of the corrugated member for guiding it in the inner cylinder and for preventing damage thereto by the pin, said last named means permitting the non-compressible fluid to flow to the space surrounding the'cor rugated member.

5. In a yieldable device for interpositioning between two members having relative movement, two telescoping cylinders closed at their outer ends, an annular corrugated element positioned axially in one of the cylinders, means for connecting one end of the element in sealed relation to the closed end of the cylinder in which it is positioned, the other end of said element being axially remote'from the attached end and capable of free movement in the cylinder, means for sealing said other end of the element to thus provide in the cylinder a separate chamber the volume 'of which corresponds to the volume within the outlines of the element between its ends and is capable of being varied by elongation and contraction of the element and a movement of the sealed end relative to the connected end, a

guide carried by the sealed end and cooperating with the cylinder wall, a substantially non-compressible fluid in the cylinders and surrounding the exterior of the element, and a compressible fluid under pressure in the separate chamber provided by the element.

STEVE SCHNELL. 

